1. Field of the Invention
The present invention relates to an emulation technique capable of imaginarily constructing an environment which allows access to, for example, an SD (Secure Digital) memory card(R) to be executed in steps of access to a floppy disk(R).
2. Description of the Related Art
In recent years, a semiconductor memory mounted on, for example, a PDA (Personal Digital Assistant), a digital camera and the like has been made smaller in size and larger in capacity in accordance with the progress of the semiconductor manufacturing technology. For example, an SD memory card(R) has a storage capacity of tens to hundreds of megabytes in a size with sides 2 to 3 centimeters long. For this reason, personal computers having slots for loading of semi-conductor memories as represented by the SD memory cards(R) instead of floppy disks(R) as standard equipment, have also been increased.
On the other hand, a request to continuously use the operation environment constructed on the floppy disk(R) has been strong. Thus, so-called emulating functions to handle a part or an entire body of a storage area of a storage medium as a different kind of storage medium have been variously proposed (for example, Jpn. Pat. Appln. KOKAI Publication No. 5-289854 and Jpn. Pat. Appln. KOKAI Publication No. 2001-290606).
With this kind of emulating function, the area for floppy disk(R) is reserved in, for example, the SD memory card(R) and the contents of the desired floppy disk(R) are copied in the area. Therefore, even if the personal computer is not equipped with a slot for floppy disk(R), the operation environment constructed on the floppy disk(R) can be continuously used with the only slot for SD memory card(R).
Incidentally, according to any conventional emulating function as disclosed in Jpn. Pat. Appln. KOKAI Publication No. 5-289854 or Jpn. Pat. Appln. KOKAI Publication No. 2001-290606, the area for the emulated storage medium is fixed in an area to which an upper-level system such as an operating system or the like cannot access. This certainly prevents the contents of the emulated storage medium from being rewritten due to carelessness. However, it is difficult for the personal computer user to intentionally rewrite the contents. Therefore, if the floppy disk(R) is emulated in a part of the storage area of, for example, the SD memory card(R), exchanging the floppy disk(R) is very difficult.
In addition, since the SD memory card(R) is subjected to specific processing that may exceed the file system standard, such as reserving the area for floppy disk(R) by operating the partition table of, for example, the SD memory card(R), the SD memory card(R) may not be subjected to general use in a device such as a digital camera, a mobile telephone or the like.